Project Summary Drug development has become an extremely expensive and time-consuming process. It is for this reason that many efforts are being made to overhaul how potential drugs are brought to market. By lowering the cost in the developmental and testing phases, the inflated end costs can be controlled. The use of model organisms as a cheaper explorative method prior to human testing has, and must continue to, become an invaluable asset. One such model organism is the small nematode species, Caenorhabditis elegans (C. elegans), which provides an excellent alternative for modeling and studying human diseases and reactions. The C. elegans genome has been completely sequenced since 1998, and the high number of genes and molecular pathways shared with humans makes them an excellent candidate for drug and other comparative studies. Their transparency and short life cycle make them fast to culture and easy to analyze. They have the added benefit of not requiring stringent animal welfare controls, which allows for simpler testing protocols. While all of these benefits make them excellent candidates for study, current technologies have limited researchers? ability to take advantage of the potential that these organisms have. Specifically, there is a need for a high-throughput 3D imaging and sorting system that can exploit the large amount of information offered by the C. elegans and is able to handle the high quantity of samples that can be prepared in a short timeframe. Current technologies involve using either a very expensive and time-intensive confocal microscope to image the animals, or a large, equally expensive, benchtop instrument (the Union Biometrica COPAS Biosort is the only C. elegans sorter on the market) to achieve sorting. Neither takes full advantage of the information that the C. elegans can provide, either taking too long and requiring the nematode to be paralyzed before imaging (confocal microscopy), or missing critical information with their insufficient imaging capacity (COPAS Biosort). These drawbacks limit the usefulness of current C. elegans analysis and sorting tools in biomedical studies and drug development, resulting in many unmet needs. Our objective in this SBIR project is to address these unmet needs by developing an acoustofluidic (i.e., the fusion of acoustics and microfluidics) based method that can perform high-resolution, high-throughput, low-cost 3D imaging and sorting without using confocal microscopy or requiring the C. elegans to be paralyzed. Our device will have the benefits of a confocal microscope concerning 3D imaging and the COPAS Biosort concerning high-throughput C. elegans sorting, while only requiring a standard fluorescent microscope. With unprecedented 3D imaging and sorting capabilities in the same device, our acoustofluidic approach will not only become a more compact and affordable replacement to the existing C. elegans analysis and sorting approaches, but also fulfill many unmet needs in both fundamental biological/biomedical research efforts as well drug development studies and toxicity testing.